great debate; major controversy
Refers to a large-scale, heated, or significant argument or discussion, often on a public or important topic.
A great debate took place in the Diet over that policy.
This issue has sparked major controversy for many years.
Compound of 大 (dai, 'big, great') and 議論 (giron, 'discussion, argument'). The exact historical derivation is uncertain, but the word follows a common pattern of prefixing 大 to intensify a noun.